EM - Escola de Minas

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Proposal for an environmentally sustainable beneficiation route for the amphibolitic Itabirite from the Quadrilátero Ferrífero - Brazil.
(2020) Gonçalves, Gizele Maria Campos; Lima, Rosa Malena Fernandes
The high world demand for iron ores opposed to the rapid exhaustion of high-grade deposits from the main producing regions around the world has motivated the search and/or improvement of beneficiation routes, which enable the economic use of iron formations previously considered marginal ores, which have the potential to considerably increase mineable reserves due to their large volume. In this study, a sample of amphibolitic itabirite from the eastern region of the Quadrilátero Ferrífero, minas Gerais, Brazil was characterized, aiming at its use in the industrial pelletizing circuit. The main physical characteristics of this ore are moisture = 10% and specific weight = 3710 kg/m3 . The ore has a high grade of loss on ignition—LOI (6.7%) and P (0.14%). Through X-ray diffractometry (XRD), optical microscopy and scanning electron microscope—SEM, the ore was found to consist of 64.5% goethite (amphibolitic, alveolar, massive and earthy); 6.8% hematite (martitic, granular and lamellar) and 0.9% magnetite. The main gangue mineral is quartz (25.5%). Based on the results of concentration tests (magnetic and flotation) performed with the studied sample, the magnetic concentration route of deslimed sample followed by the addition of slimes in magnetic concentrate can be incorporated into the pelletizing process.
Influence of cations Ca2+, Mg2+ and Zn2+ on the flotation and surface charge of smithsonite and dolomite with sodium oleate and sodium silicate.
(2017) Araújo, Ana Carolina Arantes; Lima, Rosa Malena Fernandes
using sodium oleate and sodium silicate. Microflotation test results demonstrated recoveries of 95% and 5% for smithsonite and dolomite, respectively, from 2.5 × 10−5 M sodium oleate and 50 mg/L sodium silicate at pH 9.5. The smithsonite was depressed by the cations Ca2+ and Mg2+ and, the dolomite was depressed by Zn2+ cations, which was probably caused by the reaction of these cations with the oleate anions in the solution, decreasing the concentration of collector available for adsorption onto the minerals. The powerful depression of smithsonite caused by Ca2+ cations compared with that caused by Mg2+ cations can be considered to have occurred because of the higher concentration of Ca2+ in the solution. From the zeta potential measurements at pH 9.5, we concluded that the predominant species of oleate and of sodium silicate were adsorbed onto both minerals, and the silicate species prevented the adsorption of oleate anions onto dolomite. The decrease in the negative zeta potential of both minerals after cation conditioning can be related to the electrostatic attraction between the cations and the negative sites on their surfaces. The negative zeta potential of smithsonite increased at a concentration of 1 × 10−6MCa2+ and Mg2+,whereas the potential decreases at a concentration of 1 × 10−3 M, which can be related to a lower concentration of oleate anions being available for adsorption.
Influence of sodium silicate modulus on iron ore flotation with sodium oleate.
(2013) Arantes, Renato de Souza; Lima, Rosa Malena Fernandes
This paper presents the influence of sodium silicate modulus on iron ore flotation with sodium oleate collector. Bench flotation tests were performed at pH 7 with actual iron ore from Quadrilátero Ferrífero, Brazil, with 42.8% Fe and 37.2% SiO2. Iron recovery averaged above 90% and the Fe contents in the concentrate were above 55%. The highest values of Fe grade and lowest of SiO2were obtainedwith lowlevels of pulp density and sodium silicate dosage and with high level of sodiumoleate. Increase of sodiumsilicate modulus had a small influence on response variables.

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